本文主要是介绍使用MediaProjection和MediaRecorder实现屏幕录制,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
一、实现效果
这个Demo主要是实现Android手机屏幕录制的功能,可以实现视频、音频的录制,可以选取录制视频的效果,是否开启音频录制。截图如下:
点击START按钮开始屏幕录制,这里还可以选择标清或高清视频,是否开启音频录制等;点击STOP按钮结束录制。
二、代码分析
整个Demo比较简单,只有两个类:一个是应用程序入口MainActivity,一个是具体实现录制功能的ScreenRecordService。
在MainActivity中,点击START按钮,系统向用户请求屏幕录制的相关权限,这里获取权限其实是调用 mediaProjectionManager.createScreenCaptureIntent()获得一个intent,通过 startActivityForResult(intent) 请求权限。在onActivityResult() 中响应用户动作,获得允许则开始屏幕录制。代码如下,新建MainActivity继承Activity,向其中加入以下代码:
- public class MainActivity extends Activity {
-
- private static final String TAG = "MainActivity";
-
- private TextView mTextView;
-
- private static final String RECORD_STATUS = "record_status";
- private static final int REQUEST_CODE = 1000;
-
- private int mScreenWidth;
- private int mScreenHeight;
- private int mScreenDensity;
-
-
- private boolean isStarted = false;
-
- private boolean isVideoSd = true;
-
- private boolean isAudio = true;
-
- @Override
- protected void onCreate(Bundle savedInstanceState) {
-
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
-
- Log.i(TAG, "onCreate");
- if(savedInstanceState != null) {
- isStarted = savedInstanceState.getBoolean(RECORD_STATUS);
- }
- getView() ;
- getScreenBaseInfo();
- }
-
- private void getView() {
- mTextView = (TextView) findViewById(R.id.button_control);
- if(isStarted) {
- statusIsStarted();
- } else {
- statusIsStoped();
- }
- mTextView.setOnClickListener(new OnClickListener() {
-
- @Override
- public void onClick(View v) {
-
- if(isStarted) {
- stopScreenRecording();
- statusIsStoped();
- Log.i(TAG, "Stoped screen recording");
- } else {
- startScreenRecording();
- }
- }
- });
-
- RadioGroup radioGroup = (RadioGroup) findViewById(R.id.radio_group);
- radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {
-
- @Override
- public void onCheckedChanged(RadioGroup group, int checkedId) {
-
- switch (checkedId) {
- case R.id.sd_button:
- isVideoSd = true;
- break;
- case R.id.hd_button:
- isVideoSd = false;
- break;
-
- default:
- break;
- }
- }
- });
-
- CheckBox audioBox = (CheckBox) findViewById(R.id.audio_check_box);
- audioBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
-
- @Override
- public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
-
- isAudio = isChecked;
- }
- });
- }
-
-
-
-
- private void statusIsStarted() {
- mTextView.setText(R.string.stop_recording);
- mTextView.setBackgroundDrawable(getResources().getDrawable(R.drawable.selector_red_bg));
- }
-
-
-
-
- private void statusIsStoped() {
- mTextView.setText(R.string.start_recording);
- mTextView.setBackgroundDrawable(getResources().getDrawable(R.drawable.selector_green_bg));
- }
-
-
-
-
- private void getScreenBaseInfo() {
- DisplayMetrics metrics = new DisplayMetrics();
- getWindowManager().getDefaultDisplay().getMetrics(metrics);
- mScreenWidth = metrics.widthPixels;
- mScreenHeight = metrics.heightPixels;
- mScreenDensity = metrics.densityDpi;
- }
-
- @Override
- protected void onSaveInstanceState(Bundle outState) {
-
- super.onSaveInstanceState(outState);
- outState.putBoolean(RECORD_STATUS, isStarted);
- }
-
-
-
-
- private void startScreenRecording() {
-
- MediaProjectionManager mediaProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE);
- Intent permissionIntent = mediaProjectionManager.createScreenCaptureIntent();
- startActivityForResult(permissionIntent, REQUEST_CODE);
- }
-
- @Override
- protected void onActivityResult(int requestCode, int resultCode, Intent data) {
-
- super.onActivityResult(requestCode, resultCode, data);
- if(requestCode == REQUEST_CODE) {
- if(resultCode == RESULT_OK) {
-
- Intent service = new Intent(this, ScreenRecordService.class);
- service.putExtra("code", resultCode);
- service.putExtra("data", data);
- service.putExtra("audio", isAudio);
- service.putExtra("width", mScreenWidth);
- service.putExtra("height", mScreenHeight);
- service.putExtra("density", mScreenDensity);
- service.putExtra("quality", isVideoSd);
- startService(service);
-
- isStarted = !isStarted;
- statusIsStarted();
- simulateHome();
- Log.i(TAG, "Started screen recording");
- } else {
- Toast.makeText(this, R.string.user_cancelled, Toast.LENGTH_LONG).show();
- Log.i(TAG, "User cancelled");
- }
- }
- }
-
-
-
-
- private void stopScreenRecording() {
-
- Intent service = new Intent(this, ScreenRecordService.class);
- stopService(service);
- isStarted = !isStarted;
- }
-
-
-
-
- private void simulateHome() {
- Intent intent = new Intent(Intent.ACTION_MAIN);
- intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
- intent.addCategory(Intent.CATEGORY_HOME);
- this.startActivity(intent);
- }
-
- @Override
- public boolean onKeyDown(int keyCode, KeyEvent event) {
-
- if(keyCode == KeyEvent.KEYCODE_BACK) {
- simulateHome();
- return true;
- }
- return super.onKeyDown(keyCode, event);
- }
-
- }
在ScreenRecordService中,第一步需要获得MediaProjectionManager的实例,通过它才可以获得MediaProjection的实例。然后在createMediaRecorder()方法中创建MediaRecorder的实例,并且完成对它的配置。录制的视频的质量就是在这里配置完成的,主要是setVideoEncodingBitRate(), setVideoEncodingBitRate()这两个方法控制。在配置完成后一定要记得mediaRecorder.prepare(); 并且这行代码必须在创建VirtualDisplay的实例之前调用,否则不能正常获取到 Surface的实例。新建类ScreenRecordService继承Service,在其中加入以下代码:
- public class ScreenRecordService extends Service {
-
- private static final String TAG = "ScreenRecordingService";
-
- private int mScreenWidth;
- private int mScreenHeight;
- private int mScreenDensity;
- private int mResultCode;
- private Intent mResultData;
-
- private boolean isVideoSd;
-
- private boolean isAudio;
-
- private MediaProjection mMediaProjection;
- private MediaRecorder mMediaRecorder;
- private VirtualDisplay mVirtualDisplay;
-
- @Override
- public void onCreate() {
-
- super.onCreate();
- Log.i(TAG, "Service onCreate() is called");
- }
-
- @Override
- public int onStartCommand(Intent intent, int flags, int startId) {
-
- Log.i(TAG, "Service onStartCommand() is called");
-
- mResultCode = intent.getIntExtra("code", -1);
- mResultData = intent.getParcelableExtra("data");
- mScreenWidth = intent.getIntExtra("width", 720);
- mScreenHeight = intent.getIntExtra("height", 1280);
- mScreenDensity = intent.getIntExtra("density", 1);
- isVideoSd = intent.getBooleanExtra("quality", true);
- isAudio = intent.getBooleanExtra("audio", true);
-
- mMediaProjection = createMediaProjection();
- mMediaRecorder = createMediaRecorder();
- mVirtualDisplay = createVirtualDisplay();
- mMediaRecorder.start();
-
- return Service.START_NOT_STICKY;
- }
-
- private MediaProjection createMediaProjection() {
- Log.i(TAG, "Create MediaProjection");
- return ((MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE)).getMediaProjection(mResultCode, mResultData);
- }
-
- private MediaRecorder createMediaRecorder() {
- SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
- Date curDate = new Date(System.currentTimeMillis());
- String curTime = formatter.format(curDate).replace(" ", "");
- String videoQuality = "HD";
- if(isVideoSd) videoQuality = "SD";
-
- Log.i(TAG, "Create MediaRecorder");
- MediaRecorder mediaRecorder = new MediaRecorder();
- if(isAudio) mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
- mediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
- mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
- mediaRecorder.setOutputFile(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES) + "/" + videoQuality + curTime + ".mp4");
- mediaRecorder.setVideoSize(mScreenWidth, mScreenHeight);
- mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
- if(isAudio) mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
- int bitRate;
- if(isVideoSd) {
- mediaRecorder.setVideoEncodingBitRate(mScreenWidth * mScreenHeight);
- mediaRecorder.setVideoFrameRate(30);
- bitRate = mScreenWidth * mScreenHeight / 1000;
- } else {
- mediaRecorder.setVideoEncodingBitRate(5 * mScreenWidth * mScreenHeight);
- mediaRecorder.setVideoFrameRate(60);
- bitRate = 5 * mScreenWidth * mScreenHeight / 1000;
- }
- try {
- mediaRecorder.prepare();
- } catch (IllegalStateException | IOException e) {
-
- e.printStackTrace();
- }
- Log.i(TAG, "Audio: " + isAudio + ", SD video: " + isVideoSd + ", BitRate: " + bitRate + "kbps");
-
- return mediaRecorder;
- }
-
- private VirtualDisplay createVirtualDisplay() {
- Log.i(TAG, "Create VirtualDisplay");
- return mMediaProjection.createVirtualDisplay(TAG, mScreenWidth, mScreenHeight, mScreenDensity,
- DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR, mMediaRecorder.getSurface(), null, null);
- }
-
- @Override
- public void onDestroy() {
-
- super.onDestroy();
- Log.i(TAG, "Service onDestroy");
- if(mVirtualDisplay != null) {
- mVirtualDisplay.release();
- mVirtualDisplay = null;
- }
- if(mMediaRecorder != null) {
- mMediaRecorder.setOnErrorListener(null);
- mMediaProjection.stop();
- mMediaRecorder.reset();
- }
- if(mMediaProjection != null) {
- mMediaProjection.stop();
- mMediaProjection = null;
- }
- }
-
- @Override
- public IBinder onBind(Intent intent) {
-
- return null;
- }
-
- }
由上基本就可以实现屏幕录制的功能,但是MediaProjection是在API 21中加入的,所以只能在21以上的手机上使用。在低Android版本的手机上也可以在不root的情况下实现截屏、屏幕录制等功能,但是那都只有应用程序本身占用的屏幕范围,不包括状态栏。最后记得在manifest.xml中加入以下权限:
- <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
- <uses-permission android:name="android.permission.RECORD_AUDIO" />
如果你的项目中并不需要录制音频,则 "android.permission.RECORD_AUDIO" 这句可以不要。这里录制的音频只能是来自麦克风的声音,并不能直接录制手机发出的声音,比如电话录音等。
三、总结及补充
屏幕录制的步骤大概可以总结为:1)通过MediaProjectionManager取得向用户申请权限的intent,在onActivityResult()完成对用户动作的响应;2)用户允许后开始录制,可以直接写在一个Activity里,但是像这样另外写在Service里更为妥当,录制的代码也可以单独抽出来写成一个ScreenRecorder的类;3)获取MediaProjection的实例,获取及配置MediaRecorder的实例,并记得MediaRecorder需要prepare();4)获取VirtualDisplay的实例,它也是MediaProjection, MediaRecorder完成交互的地方,录制的屏幕内容其实就是mediaRecorder.getSurface() 获得的 surface 上的内容。
如果不使用MediaProjection + MediaRecorder组合,也可以使用MediaProjection + MediaCodec + MediaMuxer组合实现相同的功能。其中各个类的作用简要总结如下:
MediaMuxer:将音频和视频进行混合生成多媒体文件,输出mp4格式;
MediaCodec:将音视频进行压缩编码,并可以对Surface内容进行编码,实现屏幕录像功能;
MediaExtrator:将音视频分路,和MediaCodec正好反过程;
MediaFormat:用于描述多媒体数据的格式;
MediaRecoder:用于录像并压缩编码,相较于MediaCodec更适合屏幕录像;
MediaPlayer:用于播放压缩编码后的音视频文件;
AudioRecord:用于录制PCM数据;
AudioTrack:用于播放PCM数据; PCM即原始音频采样数据
源码下载请点这里
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